Health professionals use a variety of small hand-held diagnostic instruments such as otoscopes, ophthalmoscopes and retinoscopes, among others, for performing specific examinations. Battery operated versions of such instruments are known, such as those described in U.S. Pat. Nos. 3,698,387 and 4,006,738 issued to Moore et al, U.S. Pat. No. 4,147,163 issued to Newman et al, and U.S. Pat. No. 5,117,424, issued to Connors. Each of the instruments described in these patents includes a grippable handle containing rechargeable batteries and a suitable instrument head that is removably attached to the top end of the handle.
As described in the latter '424 patent, interchangeable adapters can be attached to the handle to allow the contained batteries to be recharged without requiring the batteries to be removed from the instrument. The adapters include a transformer suitable for allowing the batteries contained within the handle to be recharged using either a domestic 120 volt using one of the adapters or a foreign 220 volt outlet when using another adapter. Another exemplary diagnostic instrument utilizing interchangeable adapters is described in U.S. Pat. No. 5,542,904, issued to Heine et al. In each reference, however, at least partial disassembly of the gripping handle is required in order to install the adapter of choice, this disassembly is rather cumbersome, time-consuming, and awkward.
There is an identified need to provide a battery powered diagnostic instrument which allows the contained batteries to be recharged from a variety of different power sources but without requiring removal of the batteries or disassembly or teardown of the instrument handle.